Stacker crane



Aug. 23, 1966 TAL STACKER CRANE 8 Sheets-Sheet 1 Filed Dec. l0, 1963.IIIIIL c.. c le. .UHU

aF. ARMINGTON, JR.. ETAL. 3,258,097

v vSuomen CRANE Filed Dec. 10,1963

8 Sheets-Sheet 2 7/ INVENTOR. STEM/,wr F.' HfM/NGMA/.Jk

BY #5N/ ENGEL ETI- Q.. HTOR/VEYS 8 Sheets-Sheet 3 STACKBR CRANE 5. F.ARMINGTON. JR.. ETAL.

Filed Deo.

' INVENTOR JrEwn/rr TMrn//vsrom BY Hrw/fr E/vEL l .errar/vn: l

AUI. 23. 1966 sgr. Amma-ron. Jn.. erm. 3.268.097

s. F. ARMINGTON. Jlre..v ETAL Aug. 23, 1966 8 Sheets-Sheet v Filed Dec.

'W @fram/5v5 f INVENTOIL 8 Sheets-Sheet S STACKER CRANE JIJ?? m. ma; m Ma 0 if, w r n. ZM

SW7/vf maar Aug. 23, 1966 Filed Dec.

A\lg 23. 1966 s. FfARMINGToMJR.. ETAL .3,268,097

' sTAcxER CRANE n Filed Dec. 1o, 1963 8 sheets-sheet v INVENTORl QQNWY-b w? N9uf MSN, H15, Nh.\\ AIV Anm.

Amig 23, 3956 s. F. ARMINGTON, JR., ETAL 3,268,097

STACKER CRANE Filed Dec. lo. 196s s sheets-sheet u United States PatentO 3,268,097 Y STACKER CRANE Stewart F. Armington, Jr., East Cleveiand,and Henry Engel, Euclid, Ohio, assignors to The Euclid Crane and HoistCompany, Cleveland, Ohio, a corporation of Ohio Filed Dec. 10, 1963,Ser. No. 329,415 12 Claims. (Cl. Zhi-16.4)

This invention relates to improvements in a crane for storing articlesin a warehouse, and more particularly, to a stacker crane designed tosave warehouse space and designed for a novel automatic control.

The present invention, as herein described and illustrated, comprises astorage frame having load support means provided on either side of anaisle in which a load carrying -apparatus travels both vertically andhorizontally. The load support means illustrated comprises pairs ofcantilevered arms projecting from the storage frame toward the aisle andarranged in vertical and horizontal rows whereby they dene a pluralityof horizontally spaced bays and vertically spaced load levels on eitherside of the aisle.

The stacker crane of this invention is supported on a pair of railsdisposed parallel with the aisle and suitably mounted above the storageframe on either side of the aisle. A wheeled bridge travels along therails above the aisle for horizontal movement of the stacker crane, anda trolley is, in turn, mounted upon the bridge for movement laterally ortransversely of said aisle. The trolley supports a depending mast,adapted to project `downwardly in the aisle between the rows of loadsupport arms, and a hoist mechanism for moving a hoist carriagevertically up or down said mast. The hoist carriage carries an outwardlycantilevered turret member which in turn carries a load handlingextractor fork. The extractor fork is rotatable toward either the rightor left side of the aisle and includes extractor mechanism for movingthe fork tines in between adjacent load support alms on either side `ofthe aisle for either picking up or depositing a load at the horizontaland vertical location of any of the pairs of load supporting arms. Thestacker crane is movable to and from a start position beyond the storageframe where adequate space is provided for the above referred to turningmovement of the fork. 'Ihis allows the aisle to be of minimum widthsince no turning ever takes place in the aisle.

The stacker crane of this invention may be adapted for the storage ofvarious articles and is herein illustrated as being adapted to storeelongated metal bar stock prefer- A ably carried in elongated, shallowpans for convenience in handling.

In general operation, the stacker crane is initially positioned at thestart position beyond the storage frame. Suitable controls are providedwhereby an operator can select a load support position. Upon pressing astart button, the forks will irst turn themselves toward the selectedside of the Iaisle if they are not already so facing. Because theextractor fork is only slightly narrower than the aisle, the trolley isthen caused to make a corresponding and compensating movement in theopposite direction thereby disposing the depending mast to one side ofthe center line of the aisle.

With the forks properly oriented, the bridge moves down the -aisle tothe selected bay, and the hoist carriage moves up to the selected level.The fork then moves forwardly into the storage frame, slightly above thelevel of the selected load support arms if the forks are loaded andslightly below said arms if the forks are empty. The hoist carriagemoves the fork downwardly or upwardly past the arms to deposit or pickup a load thereat after which the extractor fork moves outwardly intothe aisle, the hoist carriage lowers to a lowermost running level,

and the bridge moves in reverse back to the start position.

One of the objects of the present invention is to provide a hoistcarriage supported overhead for movement of the carriage vertically on amast and particularly adapted to present load handling forks either tothe righthand or left-hand side of an aisle along which load supportingshelf-like structures are provided. One of the advantages of themechanism herein disclosed is that the aisle need have very slightclearance on opposite sides of the hoist carriage and load forksconnected therewith, the forks being adapted to turn in either theright-hand or left-hand direction when serving load supports ondiiferent sides of the aisle.

Another object of the present invention is to provide control means forautomatically insuring that when a load is on the load carrying surfaceof the hoist carriage, it is automatically controlled to stop slightlyabove a load support after which the forks or extractor device will moveinto the load supporting area, then downward to deposit the load, thenback into the aisle. On the other hand, when the load carrying surfaceis empty, then the hoist carriage is automatically controlled to move tothe desired load support level and stop slightly below that level, afterwhich the extractor device moves into the load support area, then upwardto pick up the load and then back out into the aisle.

This invention also includes control means for insuring that a load isfirmly deposited in proper position approximately parallel to the aislebefore the mechanism can move through a cycle handling the load to orfrom a load support.

Still another improvement in the present invention is control means forinsuring that the hoist carriage is locked to the mast in case the hoistcable develops a break or a slack condition, rather than to permit thehoist carriage to be dropped suddenly.

Other objects and advantages of the present invention include theparticular design of the apparatus and parts for transporting a load toand from a storage space, all of which will be apparent from theaccompanying drawings and description.

In the drawings,

FIG. 1 is a top plan view of a warehouse area equipped with the improvedmechanism of this invention for transporting loads to and from loadsupporting shelf-like members in the warehouse;

FIG. la is a detail View showing the mechanism of FIG. 1 in oneoperative position; I

FIG. 2 is an end elevation of the same on a slightly enlarged scale;

FIG. 3 is a view taken generally along the line 3-3 of FIG. 2;

YFIG. 4 is a sectional view taken along the line 4-4 of FIG. 3;

FIG. 5 is a fragmental sectional view, enlarged, taken along the line5-5 of FIG. 4;

FIG. 6 is a sectional View taken along the line 6--6 0f FIG. 4;

FIG. 7 is an end elevational view taken along the line 7 7 of FIG. 6;

FIG. 13 is a simplified showing of the location and action of stillother limit switches;

FIG. 14 is a plan view of a control console for use with the presentinvention; and

FIGS. 15a and 15b constitute a single automatic control diagram for thestacker crane of this invention.

FIGS. 1 and 2 show one form of warehouse structure and one form of loadhandling device capable of carrying out this invention. Comment will begiven later as to other forms which might embody the same inventions.

Referring to FIGS. l and 2, the warehouse structure is defined by atleast two parallel rows of vertical posts `15 which define between theman aisle 1. Adjacent pairs of posts 15 in each row define laterally openbays 2, and in each bay, there are a plurality of vertically spaced load-supports I16 which, in this embodiment, comprise a plurality of pairsof cantilevered arms extending horizontally away from the posts atdifferent levels. It should be understood that other means might beprovided for supporting additional arms as indicated in dot-dash linesin lFIG. l at 21,6. It is only necessary for the purpose of thisinvention that there be space between the load supporting surfaces sothat the extractor fork tines may move into the load supporting area andthen vertically past the horizontal plane of coacting load supportseither upwardly to pick up a load or downwardly to deposit a load, afterwhich the extractor moves out of the load supporting area.

The load transporting mechanism is herein shown as supported fromoverhead but other types of load transporting apparatus might utilizemany of the novel features of the present invention. Again referring toFIGS. 1 and 2, an overhead bridge 17 moves parallel to the aisle 2 inthe direction of the arrow X. A trolley 18 riding on the bridgetransversely of the aisle of the warehouse carries a generally verticalmast 19 forwardly and rearwardly along the aisle while a hoist carriage20 is capable of moving up and down the mast 19 carrying an extractorfork 2'1 to the level of any pair of load supports 116 on either side ofthe aisle. The extractor fork 211 is movable either to the right or tothe left into the load supporting area or bays 2 to pick up or deposit aload as previously mentioned. The extractor mechanism need not be in theform of a fork but is so shown here, as utilized in steel warehousing,for the purpose of illustration.

The bridge 17 is herein shown as comprising two parallel bridge beams 22connected at their opposite ends by truck structures 23 which roll bymeans of wheels 24 on tracks 25 extending parallel to the aisle andmounted Von the buil-ding structure in any suitable manner. The bridge17 is caused to travel along the rails 25 by electrical power asillustrated by a reversible motor 26 (FIG. 6) which drives one or moreof the wheels 24. The trolley 18 is mounted 'by a plurality of wheels 27to roll along parallel tracks 28 mounted Von top of the bridge beams 22.This movement is at right angles to the aisle and is caused by motor 29suitably connected through mechanism 30 to one or more shafts 31 whichdrive wheels 27.

The vertical mast `19 is of any suitable strong and rigid construction.Preferably, it is formed of steel plates welded or riveted together toform a generally hollow square structure as seen in FIG. 4. Anon-circular structure is provided in the mast cross-section so that thehoist carriage 20 may be mounted for vertical travel along the mastwithout any turning relative to the mast. To this end, the mast shownhere is gene-rally square in section and has some strengthening andguiding ribs 19 extending vertically along substantially the full lengthof the mast in the mid-portion of those sides of the mast which facelongitudinally up and down the aisle. In the present embodiment, theseare solid steel bars bolted to the mast which provide a very strongstructure. The hoist carriage is fixed to a suitable sleeve-like member32 (FIG. 3) which has a central, vertical through opening 4 32 whichembraces the mast 19 including the vertical ribs 19 as best seen in FIG.4. Rigidly fastened to the upper surface of the member 32 are twoparallel L- Shape beams 33 which extend generally parallel to thewarehouse aisle. On one side -of the mast 19, the sleeve 32 and thebeams 33 support a cab 34 in which an operator may ride and in whichsuitable controls are mounted. On the opposite side of the mast, at thefar end of the beams 33, a turret bearing member 35 is rigidly securedto the beams 33 as by welding. The member 35 has a vertically extending,central cylindrical bore in which is rotatably mounted -a turret rmember36 (FIG.

6) t-o which is rigidly attached the extractor structure.

A reversible electric motor housed in the member 35 drives turret 36 andall connected parts through a reduction gearing in housing 37 indicatedon FIG. 2.

The structure supported on the turret member 36 is most clearly seen inFIGS. 6, 7 and 8. To the turret member is rigidly secured a horizontalplate 38, across one end of which is welded a structural angle member39. These p-arts support two parallel tracks or ways 4) to support theextractor during its lateral movement. In this embodiment of theinvention, the extractor takes the form of a fork although those skilledin this art will understand that it might be a platform or of some otherform. Four tines 41 of the fork are rigidly secured to a back beammember 42 which in 'turn is rigidly connected to a front wall 43 and twoside steel plate walls 44, all of which are rigidly connected to thehorizontal plate 33 and the angle member 39 previously described. Theplate members 44 are connected by an angle cross member 45 at the -topand a T-form cross member 46 at the bottom. This provides a very strongstructure. For moving the extractor along the ways 4t), a reversibleelectric motor 47 is mounted on the cross frame member 46 and connectedby drive belt 4S and suitable pulleys to gear reductions in box 49supported on plate 43. The output from the gear reduction box istransmitted from a sprocket 50 through a chain 51 to a sprocket 52rotatably mounted in the side plates 44 and by means of a shaft 53 whichcarries integral therewith a pair of pinion gears 54, each of which isdrivingly engaged with a rack mounted on the bottom of each of theparallel ways 40. The extractor moves horizontally on four rollers 56,supported by stub shafts 57 in upper, overlapping portions of the plates44. The rollers move along the ways 46 in a horizontal direction and aresupported on horizontal axes. To prevent side motion of the extractorcarriage with respect to the ways 40, rollers 58 are mounted to the sidewalls 44 on vertical axes and engage against flat, recessed 'walls 40aof the ways 46.

As previously mentioned, the hoist carriage moves vertically on the mast19 which, in turn, is supported from the overhead trolley 18. Theposition of the hoist carriage is controlled by a cable 71 which iswound on a drum 72 rotatably mounted on the trolley'18 and driven .by areversible hoist motor 73 through suitable reduction gearing in a casing74. One end of the cable is attached to the drum 72 and the other end isconnected at a bracket 75, on the trolley.

Means is provided for preventing a sudden dropping of the hoist carriageif cable 71 should break or develop lundesired slack. As best seen inFIGS. 3, 4 and 9, this comprises a roller 76 bearing against the cable71 near the point where it passes around a sheave wheel 77 which isrotatably mounted on the hoist carriage. This roller is mounted inparallel arms 78a of a bellcrank 78 pivoted on the hoist carriage at 79.Other arms 78h of said bellcrank are pivotally connected at 80 to links81 which extend vertically downwardly and have their lower endspivotally connected at S2 to wedge shape members 83 housed incomplementary wedge shape pockets 84 in the sleeve member 32. Each wedgemember 83 carries a pair of rollers 85 which normally roll with slightclearance between the rib 19 on the vertical mast and the inclined wallof a wedge shape pocket 84 as shown in FIG. 9. Springs 86, shown in FIG.4, normally urge the roller 76 against the cable 71. If the cable 71breaks, or goes slack, then the springs 86 move the bellcrank arms 78aand 781; in a clockwise direction as shown in FIG. 3 which pulls thewedge members 83 vertically upwardly and causes them to jam or wedgebetween the surface 84 of each pocket and the surface of the verticalrib 19" on the mast. This immediately stops the fall of the hoistcarriage.

FIGS. a and 15b show in diagrammatic form a simplitied, automaticcontrol system for directing the stacker crane of this invention to movefrom a start position outside the storage frame into said storage frameto pick up or deposit a load thereat. The control system includes meansfor orienting the direction of the forks either to the right or the leftand for correspondingly locating the trolley in a compensating positionon the left or the right prior to the crane moving from the startposition into the aisle between the rows of load supports. The controlsystem also includes means for automatically returning the stacker craneto its start position after delivering or retrieving a load. In theelectrical diagram as disclosed, it will be understood that for thepurposes of simplification and clarication, only those control elementsnecessary to demonstrate the workability of the present invention havebeen shown. Therefore, it will be understood by those familiar with theart that the coils and relays shown herein as single units may, inpractical application, be substituted by a number of coils or relays. Itwill be further understood that those coils designated as causingvarious elements of the stacker crane to move in a given directioncontrol suitable contacts and circuits, not herein illustrated, to causethe motors which power the designated elements to rotate forwardly or inreverse in a well known manner and that such motors would, in practicalapplication, be provided with automatic brakes for accurate stopping ofthe elements powered thereby.

Generally, all of the switches and contacts in the electrical diagramare shown in their nonnal or unactuated position in disregard to theposition of any element of the stacker crane which, in such position,might cause the switch to be otherwise than as illustrated. However, `aload detecting limit switch LS12 is shown with its contacts LS12A andLSIZB (lines 528 and 531, respectively) in the position taken when noload is on the forks. A limit switch LS6 has two sets of contacts LS6Aand LS6B (lines 522 and 537, respectively) which are actuatable onlyduring return movement of the stacker crane from the storage frametoward the start position, and each time r such limit switch is actuatedthe contacts thereof reverse their positions and remain so reverseduntil the neXt actuation of the switch. The position of the contactsLS6A and LS6B represent those taken at the beginning of a cycle when thestacker crane is in the start position. The coil contacts LL1 to LL6(lines 533, 536, 540, 542, 543 and 544) are controlled by latching coilsLLA in line 547 and LB in line 549 and are illustrated in the positioneffected by energization of latching coil LLB.

The limit switches LS13H, LS13L, LS14H and LS14L (lines 530, 531, 538and 539 respectively), are carried by the hoist carriage and arearranged as shown in the simplied drawing of FIG. 13. The mast 19 isprovided with two lsets 'of vertically aligned trips, one set beingdesignated as 64 and the other as 65 (FIG. 2). Each set of trips is oflike number with the other set, and the individual trips are staggeredso that each trip 65 is about 4" above the adjacent trip 64 of the otherset. The switches LS13H, LS13L, LS14H and LS14L, though verticallyarranged as shown in FIG. 13, are horizontally arranged whereby thelimit switches LS13H and LS14H are tripped only by the relatively highertrips 65 whereas the limit switches LS13L and LS14L are tripped only bythe relatively lower trips 64. The switches LS14L and LS14H are stop orleveling switches, the switch LS14L stopping the tines 41 of theextractor fork about 2 below the selected load support arms and theswitch LS14H stopping said tines about 2 above said arms. The levelingswitches act in conjunction with the switches LS13L and LS13Hrespectively in a manner herein later fully discussed.

The load detecting limit switch LS12 is located generally in the centerof the fork 21 as best shown in FIGS. 4 and 1l. As herein illustrated,the limit switch LS12 is mounted to the T-form cross member 46 behindthe back beam member 42 as Well shown in FIG. 6. Said limit switch LS12is actuated by one end of an elongated paddle member 92 which isdisposed beneath the back beam member 42 and is pivoted upon brackets 93carried at the rear of said back beam member. The paddle member 92 has arearwardly and upwardly projecting trip portion 94 disposed adjacent tothe actuating arm of the limit switch LS12. Said paddle member projectsforwardly underneath the back beam member 42 in the direction of thetines 41 and has, adjacent to its forwardly directed distal end, anupwardly angled portion 95. The bar stock stored in the storage `systemherein illustrated is disposed in shallow pans 100 (FIGS. l, la and 2)which are bridged across the tines 41 when carried lby the fork 21. Theangled portion 95 of the paddle member 92 projects upwardly above theupper level of the tines 41 whereby when a pan is resting upon .saidtines, said angled portion and, therefore, the entire paddle member 92,is pressed downwardly causing the trip portion 94 to pivot about thebrackets 93 in a counterclockwise direction thereby tripping the limitswitch LS12. Said limit switch LS12 is biased to the normal, nontrippedposition illustrated in FIG. 6 when no load is being carried by the fork21.

A pair of like pan positioning limit switches LS9 and LS10 are carriedat either end of the back beam member 42 as best shown in FIGS. 4 and 5.Limit switches LS9 and LS10 -are actuated by identical mechanismslocated at either end of the fork and, therefore, only the limit switchLS10 will be described in detail.

As shown in FIG. 5, the back beam member 42 has an opening 96 at thefront face thereof with a paddle member 97 being pivoted just inside theopening at the .upper end of said opening on brackets 97a. The lower endof the paddle member 97 is pivoted forwardly and outwardly beyond thefront face of the back beam member 42 a substantial distance above thetines 41 and is held in that position by a plunger 98 which is biasedforwardly by a coil spring 99. When a pan 100 is properly positionedupon the fork 21, the rear edge of said pan will be back against theback beam member 42 and will actuate the limit switch LS10 by pivotingthe paddle member 97 backwardly, pushing the plunger 98 longitudinally,and thereby pivoting the actuating member of said limit switch LS10. Thelimit switch LS9 is actuated in identically the same manner if the otherend of the pan is also properly positioned with its rear edge up againstthe back beam member 42.

The location and function of the other limit switches' shown insimplified form in FIGS. 10-12 will be readily understood from thefollowing description of the operation of the automatic controlsillustrated in the electrical diagram of FIGS. 15a and 15b.

Electrical current for the entire control system is provided across twomain leads L1 and L2. A start switch 551, biased toward the openposition at all times, has normally open contacts 552 and 553 disposedin lines 502 and 506, respectively. Closing of the contacts 552completes a circuit from the lead L1 through lines 501, 502 and parallelline 503 to energize a bridge direction coil B, a hoist direction coilH, and an extractor direction coil E. A

trolley direction coil T, in line 504 and a fork direction coil R inline 505 may also be energized by closing of contacts 552 by rst turninga selector switch 554 to the full line position as illustrated. Selectorswitch 554 has contacts 555 in line 504 in series with the coil T andcontacts 556 in line 505 in series with the coil R which, when closed asillustrated in the full line position, will cause energization -of the[coils T and R and which when open, as illustrated by the dotted lineposition, will cause said coils T and R to remain de-energized. Line501, in which the bridge directional coil B is connected, is disposed inparallel with the line 502 and has normally open contacts BI whichimmediately close upon the energization of the coil B therebymaintaining the energizati-on of coils B, H and E, as well as the coilsT and R when the selector switch 554 is in the full line positionillustrated.

A start relay coil MS is interposed in the line 506 to be energized uponthe closing of the normally open contacts 553 of the .start 'switch 551.Coil MS controls normally -open contacts MSI in the main lead LI betweenline 506 and line 508. Until contacts MSI are closed, no current issupplied to the remaining portion of the control diagram, and when saidcontacts MSI open, the entire control system is sie-energized. A relaycoil MMS is interposed in the line 508 and controls normally opencontacts MMSI in line 507 connected in parallel around the normally opencontacts 553. It will be readily understood that when the start switchSSI is closed, the coil MS is energized, the contacts MSI close, thecoil MMS is energized, and the contacts MMSI close to hold the coil MSin the energized condition. The line 508 also has interposed therein inseries with the coil MMS a limit switch LSI (see also FIG. 10). Thelimit switch LS1 is actuated by the bridge and is adapted to openmomentarily upon return movement only of the bridge simultaneously withsaid bridge returning to the start position. This momentary opening of`LSI de-energizcs coil MMS, opens the contact MMSI, de-energizes coilMS, and opens contacts MSI whereby all electrical energy to the controldiagram below the line 506 is cut off. With the start switch 551 in itsnormally open position, no current is then available across the line 506or 502 and, as will herein later be fully disclosed, the normally opencontacts BI will then be open whereby all control elements illustratedwill be completely isolated.

The operation of the stacker crane of this invention will first bedescribed in a cycle wherein the fork ZI is initially empty at the startposition and is moved into the storage frame to pick up a load andreturn it to said start position. For the purpose of describing this rstcycle, it will be assumed that, at the start position illustrated inFIG. l, the trolley is located in its right-hand position on the bridgeand the forks are oriented toward the left. This corresponds to thepositions of the fork and trolley shown generally in FIG. v1 at 200. Itwill be further assumed that the operator desires to piek up a load onthe right side of the aisle, in the manner indicated generally in brokenline at '1 in FG. 1a, whereby the forks must be first turned to theright with a corresponding leftward movement on the part of the trolley.Therefore, the operator will first turn the selector switch 554 to thefull line position as illustrated whereby to cause the forks to turn tothe right and the trolley to move to the left. The operator will alsodepress a selector switch 557 (line 515) to determine how far down theaisle the bridge is to move and a selector 558 (line 532) which willdetermine how high the hoist is to go. The switches 557 and 558`represent a plurality of switches which are connected in series with abridge counter 5159 and arhoist counter 560, respectively, and determinethe exact horizontal and vertical location of the load to be picked upby the stacker crane.

The operator then depresses the start switch 551 whereby the directioncoils B, H, E, T and R are all energized as described above and currentis made available to the remaining portion of the electrical controldiagram by the closing of the normally open contacts MSI. Energized coilB closes normally open contacts B2 in line 5-I-7 and opens normallyclosed contacts B3 in line 52,1; energized coil H closes normally opencontacts H1 in line 564 f and opens'normally closed contacts H2 in line537; energized coil E closes normally open contacts EI in line 540 andopens normally closed contacts E2 in line 544', energized coil T closesnormally open contacts TlI in line 510 and opens normally closedcontacts T2 in line 513; and energized coil R closes normally opencontacts RI in line 526 and opens normally closed contacts R2 in line527. Because the forks are oriented toward the left, a limit switch LSS(see FIG. Il) will be closed in line 524 thereby energizing a relay coilRSL.

The first movement of any element of the stacker crane will be therotation of the fork 21 from the left to the right. This is effected bythe closing of normally open contacts R1 in line 526 which therebyenergizes a rotation right direction coil RlR to cause right-'handrotation of the forks. A limit switch LSSR has normally closed contactsLSSRB, interposed in series with the right-hand direction coil, whichopen when right-hand rotation of the fork is complete thereby stoppingthe work in the right-hand position (see FIG. 11).

The trolley movement is effected by either trolley left coil TL in line5110 or trolley right coil TR in parallel line Sil-3. Because thecontacts TI are now closed and the contacts T2 are now open, only thecoil TL can be energized and this will cause the trolley to move to theleft. The trolley having been originally on the right, normally closedcontacts LSZRA of a limit switch LSZR (see FIG. l0) in line SI2 wereheld open, and the forks having been initially in the left-hand positionnormally open contacts LSSLA of a limit switch ISSL disposed in the sameline were initially closed. Line 5I?. is connected in parallel with aportion of line 516 in which said portion are normally closed contactsLSZLA of a trolley actuated limit switch LSZL (see FIG. 10) and normallyopen contacts LS3R1-A of the fork actuated limit switch LSSR. Becausethe right-hand trolley contacts LSZRA and the right-hand forks contactsLSSRA were initially open, it will be readily seen that no current wasavailable to the trolley left coil TL until the forks 21 were rotated tothe right to close the right-hand forks limit switch contacts LSSRA.This right-hand rotation of the forks deenergizes the coil R-3L in line524 by allowing the limit switch LSS to open and energizes the coil RSRin line 523 by closing a limit switch LS7 (see FIG. l1) upon completionof the right-hand rotation. Coil RSR closes normally open contact R3R 1in line 510A whereby a circuit is completed through said contacts,contacts LSZLA, contacts LSSRA now closed, contacts TI, and the trolleyleft direction coil TL. The trolley is now moved from the right to theleft and upon completing its leftward movement trips the limit switchLSZL and opens the contacts LSZLA thereby breaking the circuit andstopping the trolley on the left-hand side.

After the fork rotation and the trolley movements are completed, thebridge will move forwardly from the start position into t-he aisle ofthe -storage frame. This is effected by energization of a bridge forwarddirection coil BF in line 517 by completion of a circuit through a pairof normally closed contacts 10LI in line 517A, now closed contacts R3R2in line 517, normally open contacts LSZLB of switch LSZL, contacts R3held closed by energized coil R, now closed contacts B2, normally closedcontacts C1, and said coil BF. The normally closed contacts IOLI arecontrolled by a load relay ItlL in line 5213 which is energized by theclosing of limit switch contacts LSIZA when a load actuates the limitswitch LSIZ. Because the fork is not now carrying a load, limit s-witchcontacts LS I2AA are open, coil 101. is de-energized, and contacts IODIare closed. Contacts RSR-2 are closed because the forks are rotated tothe right thereby closing limit switch LS7 and energizing coil RSR. Thebridge can now move forwardly because the trolley is located on the leftand the normally open contacts LSZLB are closed although no movement ofthe bridge prior to this time was possible until the trolley hadcompleted its leftward movement.

As the bridge moves forwardly down the aisle, a limit switch L84 (seeFIG. l0) is sequentially tripped or momentarily closed at each verticalbay 2 by suitable trips 2a, and each closing momentarily energizes abridge counter coil BC in line 5114. Each time the counter coil BC isenergized, it indexes a wiper arm 561 of the bridge counter 559 thedistance of one contact. Eventually, the wiper arm 561 rotates intoalignment with a contact 562 corresponding to the selector switch 5157whereby a circuit is completed through the bridge counter across theline 515 to energize a coil C. Energized coil C opens the normallyclosed contacts C1 in line 517 thereby isolating the bridge forward coilBF and stopping the forward movement of the bridge.

The coil C in line 515 also controls a pair of normally open contacts C2in line 534. Contacts C2 control the energization of a hoist up coil HUand a hoist down coil HD (line 537) thereby assuring that the hoistcannot operates to lraise or lower the hoist carriage 20 until after thebridge has reached the point designated along the storage frame aisle 1.The closing of the contacts C2 completes a circuit through line 534 fromthe lead L1 through closed contacts 8L1, normally closed contacts L02,now closed contacts H1, normally closed contacts HD2 controlled by coilHD, and the coil HU. The contacts L02 are controlled by a load coil LOwhich is disposed in line 529 and which is controlled by a pair ofnormally open contacts ltlLZ now open because the load detector coil 10Lis d-e-energized. Normally closed contacts L02 are, therefore, in theclosed position, the hoist up coil HU is energized, and the hoist motormoves the empty fork 21 upwardly of the storage frame.

As the hoist carriage 20 moves upwardly, the limit switches LS13H andLS13L are sequentially tripped by the high and low trips 65 and 64respectively. The closing of the high limit switch LS13H in line S30does not complete a circuit to a hoist counter coil H7 disposed in thesame Vline because said line 530 also has a pair of normally opencontacts 1L3 now open 'because the coil 10L is de-energized. However,each closing of the low limit switch LS13L in line 531 Causes amomentary energization of said hoist counter coil H7 because a circuitis complet-ed thereto through the closed contacts LS12B of the loadsensing switch LS12 which are now closed because there is no load on thetines. The hoist counter coil H7, with each energization thereof,progressively indexes a wiper arm 563 of the hoist counter S60 toward acontact 564 connected to and in circuit with the selector switch 558.This energizes a coil CC in line 532 which closes contacts necessary forstopping the upward movement of the forks and setting the extractor intomotion.

Energized coil CC closes normally open contacts CCI in line 538,normally open contacts CC2 in line 539, and normally open contacts CCSin line 540. With the contacts CC2 closed, the loW stop limit switchLS14L is effective, upon closing, to energize a coil 8L also disposed inline 539. Energization of coil 8L simultaneously does two things: itopens the normally closed contacts SLI in line 53S to 'break the circuitand isolate the coil HU whereby the upward movement of the fork isstopped, and it also closes normally open contacts 8L2 in line 549thereby energizing the latching coil LLB in the same line. Latching coilLLB latches the latching contacts LL1-LL6 to the positions illustrated(lines 533, 536, 540, S42, 543 and S44) and at the same time closesnormally open contacts LLBl in line 548 where-by coil LLB is heldenergized regardless of whether or not contacts 8L2 remain closed.Energized coil LLB also opens normally closed contacts LLB2 in line 547thereby isolating the latching coil LLA and rendering it unenergizable.

At the same time that the energized coil 8L opened the normally closedcontacts 8L1 to stop the upward movement of the forks, it closednormally open contacts 8L3 in the line 541 thereby completing a circuitfrom the lead L1 at line S40 through the contacts CCS, contacts 8L3 inline 541, latched contacts LLS in line 542, normally closed loadcontacts LOS, now closed contacts E1, a coil EXF, a pair of normallyclosed contacts EXRl, and a pair of normally closed contacts EXl. Theenergized coil EXF causes the extractor to move forwardly or inwardly,the fork 21 being disposed about two inches below the load Supportmembers at that level due to the fact that the counting and the stoppingof the upward movement of the extractor was effected through the lowcount and stop limit switches LS13L and LS14L respectively.

By referring to FIG. 6, it will be noted that when the extractor fork 21moves into the storage frame at a pair 0f load supports 16 with thetines 41 disposed below the upper surface of the support arms, the trayis disposed in horizontal alignment with the paddle members 97 of thelimit switches LS9 and LS10 but is disposed above the level of theangled portion 9S of the paddle member 92 which actuates the loaddetecting limit switch LS12. The result is that in picking up a load,provided said load is straight with respect to the extractor fork, thecoil IOR in line 525 will always be energized -before the coil 10L inline 523. Therefore, the normally open contacts 10R1 (line 517B), 10R4(line 533B), and 10R5 (line 537B) will always close 'before the normallyclosed contacts 10L1 (line 517A), 10L4 (line 533A), and 10L5 (line 537A)open. If the load is not substantially straight and one of the switchesLS9 or LS10 is not actuated, coil 10R will yremain deenergized and itscontacts will remain open. The subsequent lupward movement of the forkwill actuate limit switch LS12 there-by opening the contacts of coil 10Lwhereby circuits across the lines 517, 533 and 537 are broken or cannotbe established.

At the limit of the inward movement of the extractor, a limit switchLS16 (see FIG. l2) in line 545 is closed thereby energizing a coil EX inseries therewith. Energized coil EX opens the normally closed contactsEX1 in line 540 to isolate the coil EXF, and the inward movement of theextractor is stopped. The coil EX also closes normally open contacts EX2in line 533 and opens normally closed contacts EX3 in line 501. Openingof the contacts EX3 isolates all of the direction coils B, H, E, T and Rwhereby all of the contacts controlled thereby are reversed or returnedto the position as illustrated in the diagram. For example, normallyopen contacts E1 in line 540 reopen and normally closed contacts E2 inline 544 close. However, there is no immediate energization of the coilEXR disposed in the same line for causing the extractor to moveoutwardly because normally open contacts L06 in line 543 are open due tothe fact that no load is on the forks and the coil LO is de-energized. Alimit switch LS15 (see FIG. 12) which is also disposed in the line 544,is closed at this time, said limit switch LS15 being adapted to closewhen the extractor moves forwardly to pick up or deposit a load andremaining closed until the extractor moves rearwardly to take the loadback out into the aisle at which point it reopens.

Since the fork has moved out of the aisle and into the load storageframe in the low position, the next movement needs to be an upwardmotion of the hoist carriage 20. This is effected by the closing of thecontacts EX2 in line 533. Assuming that the pan to be picked up from theload supports 16 is in proper alignment, it will close the two paddletype pan control limit switches LS9 and LS10 (see FIG. 11) when theextractor has moved all the way forwardly thereby energizing the pancontrol relay coil 10R in line 525. Energized coil 10R closes a pair ofnormally open contacts 10R4 disposed in line 533b in parallel with apair of normally closed contacts 10L4 disposed in line 533a. Thus, ifthe pan is straight, the circuit across the line 533 will not beinterrupted by the subsequent lifting of a load and the opening ofcontacts 10L4 due to the fact that the contacts 19114 will already beclosed. The hoist coil HU is, therefore, re-energized tomove the fork 21upwardly lby a circuit from the lead vL1 at line 534 through contactsC2, normally closed contacts SHl, contacts EXZ in line 533, bothcontacts 10L4 and 10R4, latching contacts LL1, normally closed contactsHD2, and the coil HU. As the forks move upwardly, the load is liftedfrom the load support thereby closing the contacts LS12A in line 528 toenergize the load detector coil 10L. Normally open contacts 10L2 areconsequently closed whereby the load relay L is energized. Energizedcoil L0 closes normally open contacts L01 in line 534, L03 in line 540,and L06 in line S43 while at the same time opening normally closedcontacts L02 in line 53S, L04 in line 544 and L05 in line 542.

Continued upward movement of .the now load carrying fork 21 eventuallycauses the high limit switch LS1'4H to close thereby energizing the coil8H in line 538. Energized coil 8H opens normally closed contact `8Hi1 inline 5734 thereby breaking the above described circuit to the hoist upcoil HU in line 534 to stop the upward movement of the forks. Energizedcoil SVH also closes normally open contact 8H 3 in line 540 to cause theextractor to move outwardly or rearwardly after executing its `briefupward movement. During lthi-s brief lifting movement, the limit switchLS14L in l-ine l539 ope-ned as it rode off of the low trip 6'4 so thatthe contacts SLS in line 5141 opened before the load was lifted by theforks and closed the load detector lim-it switch LS12 to cause reversalof the positions of those contacts controlled by the coil L0. N-ow,however, with the load carried by the forks, normally open contacts L06in line 5413 are closed whereby the closing of the normally opencontacts SH3 completes a circuit from the lead L1 at line 540 throughnow closed contacts C03, now closed contacts SH3, latched contacts LL6in line 543, now closed load contacts L06, limit switch 'LS/15 heldclosed because the extractor is all the way forward, normally closedcontacts HU3, normally closed contacts HB3, and the extractor reversecoil EXR in line 544. The extractor is then caused to move outwardlyinto the aisle until the limit switch LSIS is permitted t-o open iatwhich point the extractor coil EXR is isolated and the extractor stops.

At the time that the extractor moved forwardly or inwardly, it will berecalled that the innermost `motion thereof energized the coil EX inline 545 thereby causing reversal of the hoist direction contacts H1 andH2 to the position illustrated. Simultaneously therewith, however,normally closed contacts EX4 in the line 537 opened to prevent animmediate energization of the hoist down coil HD. When the extractormoved outwardly or in reverse, said extractor move-d away yfrom thelimit switch LS 16 in line 54S thereby de-energizing the coil EX andallowing the contacts EX14 to close, but the hoist down coil still couldnot be energized because a pair of normally closed contacts EXRZcontrolled by the now energized extractor reverse coil EXR were openedin the line 537. Therefore, when the extractor reaches i-ts outermost oraisle position, and the extractor reverse coil EXR is deenergized, thecontacts EXRZ are allowed to close thereby completing a circuit to thehoist down coil HD from the line L1 at line 534 through cont-acts C2,contacts EX4 in line 537, closed contacts LS6B of the llimit switch LS6,now closed contacts R5 of coil 10R, now closed conta-cts H2, normallyclosed contacts HUZ, normally closed contacts EXR2, and the coil HID.Thus the hoist begins .to move the forks in a downward direction.

At the lower limit of movement of the forks, the limit switch LS6strikes a first trip 66 (see FIG. 12) thereby opening the contacts LS6Bin line 537 and closin-g the contacts LS6A in line 522. -It will berecalled that each tripping of the switch LS6 causes it to move to theopposite position and stay there and that such tripping takes placeduring return movement of the stacker crane. Therefore, the hoist downcoil HD is now isolated by the opening of the contacts LS6B whereas acoil H9 in line 522 is energized bythe closing of the limit switchcont-acts LS6A. Energized coil H9 closes normally open contacts H91inline 519 which is connected across the lines 517 and 521. It wi-llberecalled that ythe trolley is located on the left whereby the limitswitch contacts LSZLB are held closed and'the forks are located towardthe right whereby the contacts RSRZ are also closed. Therefore, uponenergization of the coil H9, a circuit is formed from the lead line L1at line 5117 through contacts 10R1 in line 517B, now closed because thepan is straight on the forks, contacts R3R2, contacts LSZLB, contactsH91 in line 519, contacts 8H4 in line 521, contacts 8L4, now closedcontacts B3, contacts EXS controlled by the now de-energized coil EX,the bridge reverse actuating coil BR, normally closed contacts HU1, andnormally closed contacts HD1. The bridge then moves rearwardly back tothe start position at which point trips 617 (see FIG. 12) and 68 (seeFIG. 10) simultaneously respectively reset the limit switch LS6 to wherethe contacts thereof are again positioned las illustrated andmomentarily open the limit switch LS1 in line S68 whereby all electricalpower tothe control system is cut off by the de-energization of coilMMS, the opening of contacts MMSl, the de-energization of coil MS, andthe opening of contacts MSl in the lead Ll. This causes the entirestacker crane to stop ait the start position at which point the loadretrieved may be disposed of in any desired manner. It will be noted inFIG. 12 that limit switch LS6 has two actuating arms for tripping inboth a vertical and a horizont-al direction.

The second cycle of operation to be described will be one in which thefork of the stacker crane is loaded and such load is delivered from thestart position beyond the storage frame aisle to a preselected storageposition as determined by the closing of selector switches such as thoserepresented at 55.7 in li-ne 515 and 558 in line 532. For the purpose ofthe following description it will be assumed that the forks have beenloaded in any suitable manner and are oriented toward the right with thetrolley being correspondingly positioned on the left. It will be furtherassumed that it is desired by the operator to deliver a load on the leftside of the aisle opposite to that toward which the forks are initiallydirected.

To effect service to the left, the selector switch 554 in lines 504 and05 is turned to the dotted line position as illustrated wherein thecontacts 555 and S56 are opened and the trolley and fork direction coilsT and R respectively, are isolated and will remain de-energizedthroughout the entire cycle. Upon depressing the start switch 551 inlines 502 and Silo, only the bridge, hoist, and extractor directioncoil-s B, H and E will be energized by the closing of normally opencontacts 552 in line 502. Contacts B1 in line 501 immediately closethereby holding the circuit to the coils B, H and E. The closing ofnormally open contacts 553 will again energize coil MS, close contactsMS'l in the lead L1, energize the holding coil MMS in line S018, andclose the holding contacts MMSI in line 507. Thus, electrical energy isavail-able to the entire cnritrol system.

The contacts T1 and T2 in lines 510 `and 513 respectively will -be inthe position illustrated because the coil T is de-energized. The trolleynow positioned on the left, can, therefore, only move toward the rightby energization of the coil TR. With the trolley on the left, limitswitch contacts LSZLA in line 510 will be open, and with the forks onthe right the limit switch contacts LSSRA will be closed. Since thecontacts LS3LA in line 512 will be open, the trolley cannot move untilthe forks are rotated to the left to complete a circuit across said line512. Contacts R3R1 in Iline 510A will be closed because the forks are onthe right, and contacts R3L1 in line 516B will close when the forks haverotated to the left. The same will be true of contacts R3R2 and R3L2 inlines 51,7 Iand 521 of the bridge direction coils BF and lBR recannot beenergized because the contacts R3'in the same line are now open due tothe de-energized condition of coil R in line 505. With contacts R3L2 andcontacts LS2RB located inline 521^both being open as well as thecontacts B3, neither of the coils BF or BR c'anbe energized across thatline. Consequently, the r'st coil tobe energized will be the forkrotation left coil RL in line 527 by a circuit from the lead L1 throughthe now closed contacts R2, limit switch contacts LSSLB, said coil RL,normally closed contacts C3 controlled by the coil C, and normallyclosed contacts BRI controlled by vthe bridge reversing coil BR. Theforks now rotate from the right to the left closing the contacts R3L1vin linev 510A and R3L2 in line 521 by energizing the coil RSL i-n line524 when limit switch LSS closes upon complete rotation of the forks tothe left. Since the right hand trolley limit switch contacts LS2RB inline 521 are still open, there is still no energization of either bridgecoil, but the tripping of the left-hand fork limit switch LS3L closescontacts LSBLA -in line 512 and completes a circuit from the lead L1 atline 510 through the now closed contacts R3L1 in line 510B, contactsLSZRA and LS3LA in line 517, and contacts T2 in lline 513 to energizethe trolley right coil TR. At the same time, coil RL is isolated by theopening of contacts LSSLB. The trolley then moves to the right therebytripping the right-hand trolley llimit switch LS2R to complete a circuitfrom the lead -L1- at line 517 through closed contacts R1 in line 517B,held closed because the forks are carrying a properly positioned pan andcoil 10R is energized, contactsV RSLZ and LS2RB fin line 521, now closedcont-acts R4 in line S20, now closed contacts B2 and normally closedcontacts Cl-finiline 517 to the bridge forward coil BF. Thus, thebridgegs caused to move forwardly down the aisle with the forks carryinga load. It will be noted at this point that 'if the load were notproperly positioned thereby allowing one of the aznza'ggarosv :limitswitches LS9 or LS10 inline 525 to remain open,

the bridge could not move because the contacts 10Rl in line 518 wouldnot be closed and the normally-closed contacts 10L1 in line 516 would beheld open' by energized coil 10L in line 528, energizedbecause thecontacts LS12A of limit switch 1812 would be closed. Therefore, it w-illbe readily understood that the bridge cannot move into the aisle at allwith an improperly positioned load thereby yobviating any chance of acrooked loatlr striking some part of the storage frame therein.

The forwardly moving bridge counts out as before by the sequential andmomentary closings of the'limit switch LS4 lin line 514 therebysequentially and momentarily energizing the counter coil BC and indexingthewiper arm 561 of the bridge counter 559 toward the contact 562 inline with the closed selector switch 557 (line 515). When the bridgecounter counts out, coil C is energized as before thereby opening thenormally closed contacts C1 in line 517 to stop the forward motion ofthe bridge and closing the normally open contacts C2 in line 4534 -toenergize circuits to the hoist direction coils.

Because the forks are loaded and the load is'straight, contacts L01 and10R2 in line 534 are now closed. Also, energization of the 'hoistdirection coily H in line 502 has closed the normally open contacts H1in the same line. Therefore, closing of normally open contacts C2completes acircuit from the lead L1 through said contacts C2, normallyclosed contacts SHI, cont-acts L07, contacts 110R2, contacts H1,contacts HD2, to the coil HU. The hoist then moves the fork and the loadupwardly and the hoist count coil H7 in line 530 is momentarilyenergized at each level by the high count limit switch LS13H due to thefact that the normally open contacts 10L3 in line 530 are closed. Theforks being loaded, the contacts LSlZB of the limit switch LS12 in line531 are now open whereby the corresponding closings of the limit switchLS13L vor another load stored has no eileconthe count coil.' As before,the count coil selector switch 558 in line 532. When the hoist coutr'--\counts out, coil CC in vline 532 is energized as before thereby closingthe contacts CCI in line 538 to make elective the nent closing movementof the lhigh stop limit switch LS14H. The closing of limit switch LS14Henergizes the coil'SH in line 538 thereby opening the normally closedcontacts 8H1 in line 534 and stopping the above described upwardmovement of the fork. vCoil 8H also closes normally open contacts SH2 inline 547 to energize latching coil LLA by a circuit -from the lead L1through said contacts 55H2, normally closed contacts LLB2, and said coilLLA. Coil LLA immediately closes holding contac'ts LLAI in line 546 tokeep itself energized attire same time opening contacts LLAZ in line 549to isolate tihe other latching coil LLB. The effect of energizinglatching coil LLA is to 'open the contacts LLI inline 533, close thecontacts LL2 in Aline 536, close the contacts LL3 in line 540,1olose the`contacts LL4 in line 544, open the oontacts'Ll5 in line 542, and openthe contacts LL6 in line 543.v

The energized coil 8H also closes normally open ccntaots SH3 in line 540to complete a circuit from the lead L1 through'now closed contacts CC3,said contacts SH3, now closedlatching contacts LL3, load contacts L03held closed by fnow energized loadcoil LO, contacts E1 held closed byenergized coil E in line 503, the extractor tion ward coilHEXF, and thetwo normally closed contacts EXRI :and BXL The extractor therefore movesin with the load at the high position about Zmabove the lload supportmembers of the selected level. l

When lthe extractor reaches fthe extent of its forward or inward motion,the |limit switch LS16 in line 546 again closes toen'ergize thev coilEX.`This opens norm-ally closed contacts EXl in line 540 land stops thelinward :movement of the extractor. It also closes the normally 'opencontacts EX2' in line 533 but since the vnormally closed latchingcontacts LLI are now open, line 533 is not usablein the present cycle.:Normally closed contacts EX3 in line-'501 again open thereby effectingthe above describedreversing of all of the contacts controlled bythev'direction coils B, H and E. Nonnallyvclosed cont'acts EX4 in line541`are open `to assure that the tbridge cannot move in reverse.Contacts 8H4 in line 521 will alsobe open at thisv time. Another set rofcontacts EXG in line 536-will be closed by the coil EX, and this willcomplete the next available circuit which is 4from the lead L1 Tat theline 534 through contacts C2, contacts 8L1 inline 535, said contacts EX6in r'line/536, now latched contacts yLLZ i-n the same line, normallyclosed contacts HUZ and EXRZ in line 537 toi the hoist down coil HD.

The hoist will then move the forks downwardly until the low stop limitswitch LS14L in line 539 is closed-thereby energizing tfhe coil 8L andopening the contacts SLI in Iline 535. During this brief downwardmovement, the load has' been removed from the forkswith the con`sequentchanging of the contacts of the load detector limit switch LS12 to theposition as illustrated in lines 528 and 531. This isolates coils 10iJand LO Iand causes reversals ofthe contacts controlled Ithereby in theusual nia-nner.

The energization of the coil 8L in line 539 sets up the next succeedingcircuit by closing normally open contacts 8L3 in line 541 to complete acircuit from the lead L1 a-t line 540 through contacts CCS, saidcontacts 31.3 in line 541,.ncw latched contacts LL4 and mow closed loadcontacts L04 in line 544,'flmit switch LSIS which closed when theextractor moved forwardly, now closed contacts E2, normally closedcontacts HUB and HB3, and the extractor reverse coil EXR. Thus theextractor moves rearwardly or outwardlyuntil LS15 is allowed to open atwhich time the extractor stops.

The outward movement of the extractor, allowed the limit switch LS16 inline 515 to reopen thereby defenerf gizing the coil EX and allow-ing thenormally closed con tactsEX4 in line 537 to close. However, sincevthecoil "EXR in line 544 was energized before the cle-energizetion ofthe coil EX in |line 545, normally closed oontacts EXR2 in line 537prevented an immediate energization of the hoist down coil HD. With theextractor moved all the way out, the coil EX-R is now dre-energized andthe contacts EXR2 -are allowed to close whereby the hoist down coil isnow :automatically energized to move 'the empty forks downwardly untilsuch time as the limit switch LS6 is tipped to reverse the contacts LS6Aand LS6B thereby stopping the downward movement of the hoist carriageand forks 21.

As before, closing of theltimit switch contacts LS6A energizes the coilH9 and closes the contacts H91, but this |has no effect on bridge returnmotion since the contacts RSRZ and LSZLB in line 517 are both open. Thepath for energizing the bridge reverse coil BR in line 521 out ofalignment, the opening of contacts 10R1 would likewise stop the movementot the stacker crane.

' The normal, running level of the stacker crane as herein illustratedis one in which the tines are disposed just be low the lowermost levelof load supports 16. Thus, actuation of the hoist counter-,and thelvertically acting counter and leveling switches takes place above thenormal horizontal running level. The crane is positioned at this runninglevel whenever it is at the start position.v However, it will be readilyunderstood that the running level may, if desiredbe disposed at anotherlevel withv the hoist counterV counting downwardly or, in the case of anintermediate running level, both gppwardly and downwardly from a medianposition. Therefore, while the embodiment of the invention hereinillustrated and vdescribed shows a normal running'level at the bottom ofthe storage is, therefore, through the now closed contacts RSLZ andLSZRB. The bridge could not previously move .in reverse because eitherthe contacts 8H4 were open when the forks reached the high position atthef chosenvload level, the normally closed contacts EX4 were open whentheextractor was moved all the way :forwardly and LS16 in line 545 wasclosed, normally closed contacts HUI were open while the forks weremoving upwardly, or Vthe contacts HD1 were held open while the forkswere moved downwardly bythe coil HD inline 537. Now, all of thesecontacts are closed along with the contacts yB3 and 8L4 whereby thebridge reverse coil BR is immediately energized.' The contactsloLlinline517A are, ofcourse, closed at this time because there is no .load onthe fork. The result is that the bridge now returns tothe start position at which pointv the limit switch L56 is tripped to reverse theposition of the contacts LS6A `andLStiB and cause them to .return to theposition' illustrated simultaneously with the momentary opening of thelimit switch LS1 in line 508 to cut off all current to the controlsystem as described in connection with the first cycle.

It will be understood that if at the start of either cycle as describedabove the fork tand trolley are already oriented in the positionsdesired to service the sideY of the aisle selected, then the abovedescribed preliminary adjustments of fork and trolley would beunnecessary and the stacker crane, loaded or unloaded, `wouldbegin tomove immediately into the aisle as soon as the start but ton wasdepressed. It will be further noted that because of the parallelarranged contacts 10L1 and IOR! in line 517, the parallel arrangedcontacts 10L4 and 10R4' in line 533, the paraillel arranged contacts10L5, and 10R5 in line 537, and the series connected contacts 10L and10R2 in line 534, the bridge cannot move forwardly or rearwardly and thefork cannot move upwardly or downwardly with a crooked load.y If thefork goes in low, and the pan is not straight, coil10R in li-ne 525 willnot be energized, contacts 10R4 in line 533 will not be closed, and thehoist up coil HU will not'ibe energized. If the bridge is movingforwardly by the coil BF in linef517 with a load on the fork and theload is kn-ockedout of alignment thereby opening one of the limitswitches L59 or LS10, the circuit which is through the contacts 10R1inline 517B will be broken because said contacts 10R1 will will open.'It a load which has just been picked up is knocked out of alignmentwhile the forks are-moving |downwardly, the circuit will be throughcontacts 10R5 s in lme537B .and this will likewise be broken tostop themovemeneoff the loaded stacker crane. De-energization of the coil HD andclosing of the contacts HD1 in line 521 would not cause the bridge to gointo reverse because it would likewise be dependent upon pain controlcoil contacts 10Rl in line ,518 which would also immediately open. If,while the bridge is moving in reverse with a load back toward the startposition said load is knocked frame, the invention is not intended to belimited to that arrangement.' It will be further readily understood thatalthough the present embodiment cf the control means determinessequential movements of the bridge and hoist carriage, these motions maybe effected simultaneously throughout at least-a portion ofthcirmovements if so desired.`

The present embodiment of the invention illustrates a use of the stackercrane in connection with a storage frame `having a'lsi'ngle aisle alongwhich the crane travels. A

number of such aisles may be serviced by a single crane by increasingthe length of the bridge 17 and the distance between thetracks 25whereby said bridge spans a number of aisles ot the type illustrated. f

It willbe understood that many other changes in the details of' theinvention as herein'described and illustrated maybe made without,however, departing from the spirit thereof or the scope of the appendedclaims.

What is claimed is: t

1. Load transfer apparatus having loadhandling means movable verticallyvand horizontally in an aisle between vertically 'and horizontallyspaced load support means comprising` overhead carrier means movableparallel with said aisle;a trolley movable transversely of said aisle onsaid carrier; power means for moving said trolley; a mast depending fromsaid trolleyvandl laterally movable said aisle by said trolley; Vsaidload handling means carried by said mast; said load handling means beingmovable up and down said mast and having generally horizontal,

cantilcvered liftingmeans rotatable from one side of said aisle totheother and adapted to pick up o r deposit a load from any of said loadsupport means on either side of said aisle; power means for rotatingsaid lifting means; power means for moving said load handling means upand down said mast; saidtrclley adapted to position said mast toward oneside of said aisle when said cantilevered litting means is orientedtoward the other side of said aisle in such manner as to minimize thenecessary width of said aisle for :allowing vertical andhorizontalmovement of said load handling means in said aisle; anda safety interl at1nel movable across said bridge` transversely tossici" lock connectionbetween said trolley moving power means and said power means forrotating said lifting means enabling operation of said power means formoving said load handling means up and down said mast only when saidmast and said lifting means are orientedy toward opposite sides of saidaisle. l

2. load transfer and storage apparatus comprising a storage frame havingparallel rows of vertically and horizontally spaced loadA support meansdefining van aisle therebetween and opening into said aisle; a bridgespanning said aisle and movable parallel with and above said aisle;

aisle; a mast depending from said trolley in general ulign- @Artena-withsaid aisleiandsltiftable laterally of said aisle by said trolley; ahoist carriage vertically movably mounted on said mast; a turret carriedby said hoist carriage; an extractor .fork carried by said turret androtatable thereby toward said load support means on either sideof saidaisle; Said extractor forli comprising means carrying gcnerallyhorizontally directed fork tines and means for moving said tineshorizontally relative to said hoist carriage out of said aisle and intothe storage area of said storage frame; power means for rotating saidfork tines toward one or the other sides of said aisle, shifting saidtrolley on said bridge in a compensating direction opposite to thedirection of said tines, moving said hoist carriage upwardly anddownwardly of said mast to and from the different levels of said loadsupports, and moving said bridge along said aisle to the differenthorizontal positions of said load support means; and automatic controlmeans for sequentially causing said tines to be oriented toward one sideof said aisle and said trolley to be shifted toward the other side ofsaid aisle :at a start position beyond said`storage frame, said bridgeto move longitudinally of said. aisle to a preselected horizontalposition and said hoist carriage to move vertically to a preselectedlevel and stop slightly -above or below a selected load support means,said fork tines to move into said storage frame, said hoist carriage tomove vertically past the level of said selected load support means todeposit a load thereat or pick up a load therefrom, said fork tines tomove b-ack into said aisle, and said hoist carriage to move verticallyand said bridge to move horizontally back to said start position.

3. Load transfer and storage apparatus comprising a storage frame havingparallel rows of vertically and horizontally spaced load support meansdefining an aisle there# between and opening into said aisle; a bridgespanning said aisle and movable parallel with and above said aisle; atrolley movable across said bridge transversely to said aisle; a mastdepending from said trolley in general alignment with said aisle andshiftable laterally of said aisle by said trolley; a hoist carriagevertically movably mount-` ed on said mast; an extractor carried by saidcarriage and rotatable thereby toward said load support means on eitherside of said aisle; said extractor comprising a generally horizontallydirected load surface and meansfor moving said load surface horizontally`relative to said hoist carriage out of said aisle and into a l.storagearea of said storage frame; power means for rotating said load surfacetoward one or the other sides of said aisle, shifting said trolley onsaid bridge in a compensating direction opposite to the direction ofsaid load surface, moving said hoist carriage upwardly and downwardly ofsaid mast to and from the different levels of said load supports, andmoving said bridge along said aisle to the diierent horizontal positionsof said load support means; and control means for actuating said powermeans including means responsive to said load surface turned toward oneside of said aisle causing said trolley to automatically shift to theother side of said aisle and means responsive'to said load surfaceturned toward said other side of said aisle causing said trolley toautomatically shift to said one side of said aisle.

4. Load transfer and storage apparatus comprising a storage frame havingparallel rows of vertically and horizontally spaced load support meansdening an aisle therebetween and opening into saidaisle; 'a bridgespanning said aisle and movable parallel with and above said aisle; atrolley movable across said bridge transversely to said aisle; a mastdepend-ing from said trolley in general alignment with said aisle andshiftalble laterally of said aisle -by said trolley; a hoist carriagevertically movably mounted on said mast; a turrent carried by said hoistcarriage; an extractor fork carried by said turrent and rotatablethereby toward said load support means on either side of said aisle;said extractor fork comprising means carrying generally horizontallydirected fork tines and means for moving said tines horizontallyrelative to said hoist carriage out of said aisle and into the storagearea of said storage frames; power means for rotating said rfork tinestoward one or the other sides of said aisle, shifting said -trolley onsaid bridge in a compensating direction opposite to the direction ofsaid tines, moving said hoist carriage upwardly and downwardly of saidmast to and from the different levels of said load supports, and movingsaid bridge along said aisle to the'different horizontal positions ofsaid load support means; load position control means act-uatable by aload disposed in a predetermined position upon said tines; load detectorcontrol means actuatable'by a loaden sa-id tines; said power means forsaid bridge and said hoist carriage responsive to said load positioncontrol means in the unactuated condition and said load detector controlmeans concurrently in the actuated condition whereby said bridge andsaid hoist carriage will not move.

5. Load transfer and storage apparatuscomprising a storage framehaving'parallelrows of vertically and horif zontally spacedA loadsupport means defining an aisle therebetween and opening into saidaisle; abridge spanning said aisle andmovable parallel with and abovesaid aisle; a trolley movable across said bridge. transversely to saidaisle; a mast depending from said trolley in gen-A eral alginment withsaid aisle andshiftable llaterally of said aisleby said trolley; a hoistcarriage vertically movably mounted on said mast; a turretcarried bysaidhoist carriage; an extractor lfork carried by said turret and rotatablethereby toward said load support means on either side of said aisle;said extractor fork comprising means carrying generally horizontallydirected fork tines and means for moving said tineshorizontally relativeto said hoist carriage out of the aisle and into the storage area ofsaid storage frame; power means for rotating said fork tines toward oneor the other sides of said aisle, sh-ifting said trolleyon saidb-ridge'in a compensating direction opposite to the direction of saidtines, moving said hoist carriage `upwardly and downwardly of said mastto and yfrom the different levels ofsaid load supports, and moving saidbridge along said aisle to the dif-A ferent horizontalpositions of -saidload support means; electric control means lfor said apparatus includinga pair of vertically spaced, high and low counterswitches movable withsaid hoist carriage; two sets of vertically spaced trips carried by saidmast, each trip of one said set being disposed above the level of acorresponding trip o-f the other` set with the higher trips actuatingthe rhigh counter switch and the lower trips actuating the low counterswitch; a vertical counter for selectively determining the level atwhich said fork tines arey to st-op for retrieving or depositing a load;said counter responsive to either of said counter switches; a loaddetector switch carried by said fork tines and actuatable by a load onsaid tines; said counter responsive Vto said detector switch wherebywhen said detector switch is actuated, said counter responds only to thetripping of said high counter switch, and when said detector switch isunactuated, said counter switch responds only to the tripping of saidlow counter switch.

6. In a load storage apparatus, a vertically xed mast; a plurality ofvertically spaced load support means defining a vertical storage areadisposed adjacent to said mast; a load carrier movable vertically onsaid mast; power means for moving said carrier; electric control meansfor said apparatus including a pair of vertically spaced, high and lowercounter switches movable with said carrier; two sets of verticallyspaced trips carried by` said mast, each trip of one said set beingdisposed above the level-of a corresponding trip of the other set withthe higher trips actuating the high counter switch and the lower tripsactuating the low counter switch; a vertical counter means forselectively determining the level at which said load carrier is to stopf-or retrieving or depositing a load; said counter means responsive toeither of said counter switches; a load detector switch carried by saidload carrier and actuatable by a load on said carrier; said countermeans responsive to said detector switch whereby when said detectorswitch is actuated, said counter means responds only to the tripping ofsaid high counter switch, and when said detector switch is unactuated,said counter means responds only to the tripping of said low counterswitch.

7. In a storage apparatus as set forth in claim 6; said load carriercomprising a horizontally movable extractor having a cantilever liftmember; control means for causing said carrier t-o move upwardly alongsaid mast to a position slightly above or below a load support means,said extractor to move said lift member into the vertical storage areaof said support means, said carrier to move said lift member through thehorizontal plane of said support means for picking up or depositing aload thereat, and said extractor to move said lift member horizontallyaway from said support means; high and low carrier stop switches movablewith said carrier, disposed below saidA high and low counter switchesrespectively, and actuated by said higher and lower trips respectively;sai-d stop switches responsive to said counter means whereby when saidcounter means counts out by the last actuation of a counter switch, saidcarrier is stopped by the stop switch immediately therebelow.

`8. In storage apparatus as set forth in claim 7; extractor power meansfor moving said lift member into the vertical storage Iarea of saidsupport means; said extractor power means being responsive to both ofsaid stop switches whereby said extractor moves said iift member intothe vertical storage area of said support means upon actuation of eitherof s-aid stop switches to stop the movement of said carrier.

9'. In storage .apparatus as set forth in clai-m 8; lim-it switch meansactuated upon the complete inward movement of said lif-t member; saidiirst mentioned power means responsive to actuation of said limit switchmeans to cause said carrier to move said lift member through thehorizontal plane of said supp-ort means in a short vertical movement;said iirst mentioned power means being further responsive to said stopswitches whereby when said carrier is initially stopped by actuation ofone of said stop switches, sai-d short vertical movement is terminatedupon actuation of the other stop switch.

10. Load transfer and storage apparatus comprising a storage framehaving parallel rows of vertically and horizontally spaced load supportmeans defining an aisle therebetween and opening into said aisle; abridge spanning said aisle and movable parallel with and above saidaisle; a trolley movable across said bridge transversely to said aisle;a mast depending from said trolley in general alignment with said aisleand shiftable laterally of said aisle by said trolley; a hoist carriagevertically movably mounted on said mast; a turret carried by said hoistcarriage; an extractor fork carried by said turret and rotatable therebytoward said load support means on either side of said aisle; saidextractor fork comprising means carrying generally horizontally directedfork tines and means for mov-ing said tines horizontally relative tosaid hoi-st carriage out of said aisle and into the storage area of saidstorage frame; power means for rotating said fork tines toward one orthe other sides of said aisle, shifting said trolley on said bridge in acompensating direction opposite to the direction of said tines, movingsaid hoist carriage upwardly and downwardly of said mast to and from thedifferent levels of said load supports, and moving said bridge alongsaid aisle to the different horizontal positions of said load supportmeans; controls for said apparatus including control means responsive tosaid fork tines turned either toward one side of said aisle or theother; control means responsive to said trolley positioned eitheradjacent to one side of said aisle or the other; said power means fo-rsaid kbridge responsive to both said control means whereby said bridgecannot move unless said fork tines and said trolley are -oppositelyoriented relative -to said aisle.

11. Storage apparatus comprising a storage frame having parallel rows ofvertically and horizontally spaced load support means defining an aisletherebetween; a bridge spanning said aisle and movable parallel with and.above said aisle; a trolley movable across said bridge transversely tosaid aisle; a mast depending from said trolley into said aisle andshiftable laterally of said aisle by said trolley; a hoist carriagevertically mov-ably mounted on said mast; a load extractor mechanismrotatably carried by said carriage and rotatable toward said loadsupport means on either side of said aisle; said mechanism comprisingmeans carrying generally horizontally directed load lifting means andmeans for moving said load lifting means horizontally relative to saidhoist carriage out of said aisle and into the storage area oi saidstorage frame; and power means operatively associated with control meanseffective in an automatic cycle for rotating said mechanism toward oneor the other sides of said aisle, shifting said trolley on said bridgein a compensating direction opposite to the direction of said loadlifting means', moving said hoist carriage upwardly and downwardly ofsaid mast to and from the different levels of said load supports, andmoving said bridge along said aisle to the different horizontalpositions of said load support means.

12. In a warehouse system lfor moving loads into and out of storageracks having load receiving stations at different level-s locatedadjacent an aisle, a carrier having a load supporting means movablealong said aisle and to various levels of said racks and into and out ofsaid racks to deposit and pick up loads, power means for moving saidcarrier and for moving said load supporting means into and out of saidracks with vertical manipulation to deposit and pick up loads, a seriesof high and lower level indicators on said carrier for stopping saidload support means respectively above or below a series of associatedload receiving stations, two level detectors responsive respectively oneto said high level indicators and one to said lower level indicators, aload detector device carried by said loa-d supporting means and actuatedby a load thereon, andoperative connections causing said high leveldetectors to respond only to said load detector device in actuatedcondition and causing said lower level detectors to respond only to saidload detector device in unactuated condition.

References Cited by the Examiner UNITED STATES PATENTS 1,108,723 8/1914Dolph 187-88 1,389,867 9/1921 Griffin f 187-88 X 2,737,303 3/1956 Heldet al. 214-164 2,765,928 10/1956 Riemenschneider 214--164 X 2,869,7391/.1959 Davis 214-730 X 2,899,087 `8/ 1959 Jacobsen.

3,034,675 5/1962 Quayl 214--16.4 X 3,049,247 8/ 1962 Lemelson 214-164FOREIGN PATENTS 154,013 11/ 1953 Australia. 625,865 8/ 1927 France.1,072,557 12/ 1959 Germany.

GERALDI M. FORLENZA, Primary Examiner.

R. B. JOHNSON, Assistant Examiner.

1. LOAD TRANSFER APPARATUS HAVING LOAD HANDLING MEANS MOVABLE VERTICALLYAND HORIZONTALLY IN AN AISLE BETWEEN VERTICALLY AND HORIZONTALLY SPACEDLOAD SUPPORT MEANS COMPRISING OVERHEAD CARRIER MEANS MOVABLE PARALLELWITH SAID AISLE; A TROLLEY MOVABLE TRANSVERSELY OF SAID AISLE ON SAIDCARRIER; POWER MEANS FOR MOVING SAID TROLLEY; A MAST DEPENDING FROM SAIDTROLLEY AND LATERALLY MOVABLE IN SAID AISLE BY SAID TROLLEY; SAID LOADHANDLING MEANS CARRIED BY SAID MAST; SAID LOAD HANDLING MEANS BEINGMOVABLE UP AND DOWN SAID MAST AND HAVING GENERALLY HORIZONTAL,CANTILEVERED LIFTING MEANS ROTATABLE FROM ONE SIDE OF SAID AISLE TO THEANOTHER AND ADAPTED TO PICK UP OR DEPOSITE A LOAD FROM ANY OF SAID LOADSUPPORT MEANS ON EITHER SIDE OF SAID AISLE; POWER MEANS FOR ROTATINGSAID LIFTING MEANS; POWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UPAND DOWN SAID MAST; SAID TROLLEY ADAPTED TO POSITION SAID MAST TOWARDONE SIDE OF SAID AISLE WHEN SAID CANTILEVERED LIFTING MEANS IS ORIENTEDTOWARD THE OTHER SIDE OF SAID AISLE IN SUCH A MANNER AS TO MINIMIZE THENECESSARY WIDTH OF SAID AISLE FOR ALLOWING VERTICAL AND HORIZONTALMOVEMENT OF SAID LOAD HANDLING MEANS IN SAID AISLE; AND A SAFETYINTERLOCK CONNECTION BETWEEN SAID TROLLEY MOVING POWER MEANS AND SAIDPOWER MEANS FOR ROTATING SAID LIFTING MEANS ENABLING OPERATION OF SAIDPOWER MEANS FOR MOVING SAID LOAD HANDLING MEANS UP AND DOWN SAID MASTONLY WHEN SAID MAST AND SAID LIFTING MEANS ARE ORIENTED TOWARD OPPOSITESIDES OF SAID AISLE.
 12. IN A WAREHOUSE SYSTEM FOR MOVING LOADS INTO ANDOUT OF STORAGE RACKS HAVING LOAD RECEIVING STATIONS AT DIFFERENT LEVELSLOCATED ADJACENT AN AISLE, A CARRIER HAVING A LOAD SUPPORTING MEANSMOVABLE ALONG SAID AISLE AND TO VARIOUS LEVELS OF SAID RACKS AND INTOAND OUT OF SAID RACKS TO DEPOSITE AND PICK UP LOADS, POWER MEANS FORMOVING SAID CARRIER AND FOR MOVING SAID LOAD SUPPORTING MEANS INTO ANDOUT OF SAID RACKS WITH VERTICAL MANIPULATION TO DEPOSITE AND PICK UPLOADS, A SERIES OF HIGH AND LOWER LEVEL INDICATORS ON SAID CARRIER FORSTOPPING SAID LOAD SUPPORT MEANS RESPECTIVELY ABOVE OR BELOW A SERIES OFASSOCIATED LOAD RECEIVING STATIONS, TWO LEVEL DETECTORS RESPONSIVERESPECTIVELY ONE OF SAID HIGH LEVEL INDICATORS AND ONE TO SAID LOWERLEVEL INDICATORS, A LOAD DETECTOR DEVICE CARRIED BY SAID LOAD SUPPORTINGMEANS AND ACTUATED BY A LOAD THEREON, AND OPERATIVE CONNECTIONS CAUSINGSAID HIGH LEVEL DETECTORS TO RESPOND ONLY TO SAID LOAD DETECTOR DEVICEIN ACTUATED CONDITION AND CAUSING SAID LOWER LEVEL DETECTORS TO RESPONDONLY TO SAID LOAD DETECTOR DEVICE IN UNACTUATED CONDITION.